Fig. 3

The % freezing values during the first four trials of extinction 1 （First 4）, contextual memory test（contextual test）, cued memory test（cued test） and renewal test. Fear extinction sessions were performed at 12 weeks of age. A contextual test, cued test and renewal test were performed at 90 weeks of age. All data points are the means ± SEM. **p＜0.01 indicates a statistically significant difference from the first 4 trials of extinction phase 1.